Donor‐Interacting Arylated Carbazole Self‐Assembled Monolayer Enables Highly Efficient and Stable Organic Photovoltaics

Abstract Carbazole‐derived self‐assembled monolayers (SAMs) are promising materials for hole‐extraction layer (HEL) in conventional organic photovoltaics (OPVs). Here, a SAM Cbz‐2Ph derived from 3,6‐diphenylcarbazole is demonstrated. The large molecular dipole moment of Cbz‐2Ph allows the modulation of electrode work function to facilitate hole extraction and maximize photovoltage, thus improving the OPV performance. Additionally, the flanking aryls of Cbz‐2Ph help establish CH‐ π interactions for forming a dense and well‐organized SAM HEL and exhibit stronger van der Waals interactions with the donor PM6 than acceptor BTP‐eC9. The stronger SAM‐donor interactions modulate the PM6 distribution in PM6:BTP‐eC9 bulk‐heterojunction film, leading to PM6 enrichment near HEL to facilitate efficient hole extraction to the ITO anode in conventional p–i–n OPVs. Consequently, binary PM6:BTP‐eC9‐based devices incorporating the Cbz‐2Ph HEL demonstrate an impressive efficiency of 19.18%. These cells also showcase excellent operational stability, with a T 80 lifetime of ≈1260 h at the maximum power point, over 10 times longer than those using the traditional PEDOT:PSS HEL ( T 80 ≈96 h). Furthermore, the universal applicability of Cbz‐2Ph as a HEL is evident through its successful implementation in PM6:BTP‐eC9:L8‐BO‐F‐based ternary devices and PM6:BTP‐eC9‐based printed OPV devices, achieving a PCE of 19.30% and 16.96%, respectively.